/*
 * Copyright (C) Antonio Ramon Morcillo
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package soft.xitxarello.su.helpers;

import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
import android.content.res.Resources;

/**
 * Helper for determining if the configuration has changed in an interesting way
 * so we need to rebuild the app list.
 */
public class ConfigChangesHelper {

    // Device configuration information that can impact the resources the
    // application retrieves.
    final Configuration mLastConfiguration = new Configuration();

    // Device display density.
    int mLastDensity;

    /**
     * Ask for configuration changes.
     * 
     * @param res Resources of an application.
     * @return true if last configuration has been changed.
     */
    public boolean applyNewConfig(Resources res) {

        // Copy the fields from delta into configChanges as bit mask of the
        // changed fields.
        int configChanges = mLastConfiguration.updateFrom(res.getConfiguration());

        // Flag to recognize density changes.
        boolean densityChanged = mLastDensity != res.getDisplayMetrics().densityDpi;

        // When last configuration has been changed return true
        if (densityChanged || (configChanges & (ActivityInfo.CONFIG_LOCALE
                | ActivityInfo.CONFIG_UI_MODE | ActivityInfo.CONFIG_SCREEN_LAYOUT)) != 0) {
            mLastDensity = res.getDisplayMetrics().densityDpi;
            return true;
        }
        return false;
    }
}
